The way JavaScript works is we can do scripts as an inline block:

Or, if the script should be fetched from the network…

With CSS, we can do an inline block of styles:

So why not

? Instead, we have .
Harry Roberts asked about that the other day on Twitter:
Can any W3 historians tell us why it’s `` and not `

declares a block of rules for this page only
— Bruce Lawson (@brucel) November 29, 2018
I sort of get that. The location in the document matters with src, but not with — that relates to the entire document instead. I guess the crack in that reasoning is that the order of stylesheets does matter for order-specificity, but I take the point.
The W3C chimed to confirm that logic:
(2/2) and the original